Scanning device



P ,1939. K. SCHLESINGER 2,173,501

SCANNING DEVICE Filed Aug. 6, 1957 2 Sheets-Sheet l EX/M P 1939. K. SCHLESINGER 2,173,501

SCANNING DEVICE Filed Aug. 6, 1937 2 Sheets-Sheet 2 Patented Sept. 19, 1939 UNITED STATES PATENT OFFICE SCANNING DEVICE.

Kurt Schlesinger, Berlin, Germany, assignor to Radioaktiengesellschaft D. S. Loewe, Berlin- Steglitz, Germany Application August 6, 1937, Serial No. 157,721 In Germany August 8, 1936 Claims. (01. 178-16 It is well known in the television are to use the shaft of the interceptor 4 a corresponding inscanning discs having a multiple spiral of aperclination the disc is replaced by a conical wheel tures or lenses and to clear the single turns one of the corresponding aperture angle stiffened by after the other by means of an interceptor havthe border ll. The conical part 42 is provided 5 ing one spiral aperture and rotating at a correwith the spiral aperture 43. The form of the 5 spondingly lower speed. By practical reasons it latter is better to be recognized in Fig. 2. The is impossible to arrange both discs closed tospiral is interrupted by two spokes l4, l5 supgether, so that the shadow of one disc onto the porting the border. Its pitch corresponds to the other is not very sharp. It has also been prototal radial width of the multiple spiral of the posed to project the scanning disc by an objective scanning disc. 10 sharply onto the interceptor, i. e. to arrange A fixed diaphragm 19 having an opening 23 both in subsequent image planes of the optic defining the size of the frame may be arranged system. In this arrangement the full light of closed to the interceptor 3 before or after it. the light source was projected onto the scanning The interceptor may also be used for the gendisc, thus heating the latter in a troublesome eration of the frame synchronising impulses. 15 degree, particularly if it is running in the vac- For this purpose outside of the spiral 43 (Fig. 2) uum. Also by other reasons this arrangement two circumferential slots 20a and 2% are prohas disadvantages. vided. The light passing through them is con- According to the invention both discs are also ducted, e. g. by a prism M (Fig. 1), to a special 20 arranged in subsequent image planes of the optic photo-cell 45 or even to the image photo-cell. 20 system, but so that the light ray passes the scan- Thus at each turn of the interceptor two synning disc after the interceptor. chronising impulses are generated. In order to The invention will fully appear from the foladjust the intensity of these impulses and to lowing description in which reference will be bring it in accordance with the video signals a made to the accompanying drawings in which fine gap 2i adjustable by means of a screen 22 25 Fig. 1 shows diagrammatically the optic armay be provided on the diaphragm i9. rangement, It has been found to be particularly conveni- Fig. 2 an interceptor according to the invenent to break the comparatively long way of the tion, light by means of a mirror. Fig. 3 shows the Fig. 3 a modification of the arrangement of arrangement then resulting, which can be ac- 30 Fig. 1. commodated within a very small space. Motor 9,

It is supposed that the apparatus is provided scanning disc 8, reproducing objectives I9 and with a device correcting in a known manner the II, film l2 and machine l8 operating it are arkeystone effect produced by the use of spirally arranged on a table ll. Below the table I! there apertured scanning discs by inclining the shaft is arranged the light source I with reflector 2 35 of the scanning disc towards the optic axis by an and condenser 3, the interceptor 4, the objectives angle on. 6 and I and the vertical mirror I6.

In Fig. 1, I is an arc lamp, which by way of a The interceptor is here e. g. mounted on a verconcave reflector 2 and a condenser 3 lights a tical shaft; consequently a cone 4 having a more peculiarly formed conical intercepting disc 4. acute angle is to be used. 0

The intercepting disc 4 is driven by the motor 5 I claim: and is by means of the objectives 6 and l repro- 1. In a television transmitter a scanning arduced onto the scanning disc 8 driven by the rangement comprising a source of light, a light synchronous motor 9 with 2 to 4 times the cirbeam concentrating device, a rotating interceptor cumferential velocity of 5. The scanning disc 9 diaphragm, a scanning disc having a spiral of 45 is projected by the objectives IE1 and H onto the apertures of more than one turn, a film to be inclined plane of the film E2 to be transmitted. scanned and two Optica Sy for projecting After it the photo-cell (not shown) is placed. the plane of said interceptor on said disc and of As the shaft of the disc has to be inclined tosaid disc on the film, respectively, said inter- 0 wards the optic axis by the said angle a and, on ceptor having a conical border being provided the other hand by mechanical reasons is horiwith a spiral aperture of one turn for uncoverzontal, the optic axis must be inclined towards ng alternately One Of Said disc Spiral s. the the horizontal by the angle 0:. The operating shaft of said disc and that of said interceptor part of the surface of the interceptor has to be being horizontal.

65 vertical towards the optical axis. Instead to give 2. In a television transmitter a scanning arrangement comprising a source of light, a light beam concentrating device, a rotating interceptor diaphragm, a scanning disc having a spiral of apertures of more than one turn, a film to be scanned and two optical systems for projecting the plane of said interceptor on said disc and of said disc on the film, respectively, said interceptor having a conical border being provided with a spiral aperture of one turn for uncovering alternately one of said disc spiral turns, the shaft of said disc and that of said interceptor being horizontal, said interceptor being arranged between light source and scanning disc.

3. In a television transmitter a scanning arrangement comprising a source of light, a light beam concentrating device, a rotating interceptor diaphragm, a scanning disc having a spiral of apertures of more than one turn, a film to be scanned and two optical systems for projecting the plane of said interceptor on said disc and of said disc on the film, respectively, said light beam passing in a straight line inclined to the horizontal from said light source to said film and perpendicularly through said, interceptor, and, for correcting the keystone distortion, aslant through said disc, said interceptor having a conical border being provided with a spiral aperture of one turn for uncovering alternately one of said disc spiral turns, the shaft of said disc and that of said interceptor being horizontal.

4. In a television transmitter a scanning arrangement comprising a source of light, a light beam concentrating device, a rotating interceptor diaphragm, a scanning disc having a spiral of apertures of more than one turn, a film to be scanned and two optical systems for projecting the plane of said interceptor on said disc and of said disc on the film, respectively, said interceptor having a vertical shaft and a conical portion being provided with a spiral aperture of one turn for uncovering alternately one of said disc spiral turns, the shaft of said disc being horizontal.

5. In a television transmitter a scanning arrangement comprising a source of light, a light beam concentrating device, a rotating interceptor diaphragm, a scanning disc having a spiral of apertures of more than one turn, a film to be scanned and two optical systems for projecting the plane of said interceptor on said disc and of said disc on the film, respectively, said interceptor having a vertical shaft anda conical portion beingprovided with a spiral aperture of one turn for uncovering alternately. one of said disc spiral turns, the shaft of said disc being horizontal, means for shortening the total length of the arrangement, said means consisting of a mirror situated between said disc and said interceptor, said mirror reflecting the light ray at an acute angle.

KURT SCHLESINGER. 

